This is for a monster I've been working on; technically it's a large arachnid, but it's also sentient and its venom has freaky magical qualities so I'm not sure which above type is more fitting (last time I checked Magical Vermin wasn't a type ).

it is also possible to use vermin with intelligence; most are "mindless" (quality, no INT score) & lack skill points & feats, but the rules allow them to exist. Your monster sounds like a magic beast though